U.S. patent application number 13/259909 was filed with the patent office on 2012-02-23 for resin composition and multilayered structure.
This patent application is currently assigned to KURARAY CO., LTD.. Invention is credited to Kouta Isoyama, Hiroyuki Ono, Tatsuya Oshita, Hidekazu Saitou.
Application Number | 20120045653 13/259909 |
Document ID | / |
Family ID | 42828177 |
Filed Date | 2012-02-23 |
United States Patent
Application |
20120045653 |
Kind Code |
A1 |
Isoyama; Kouta ; et
al. |
February 23, 2012 |
RESIN COMPOSITION AND MULTILAYERED STRUCTURE
Abstract
A resin composition, contains: a thermoplastic polyurethane (A);
a thermoplastic polyurethane (B); and an ethylene-vinyl alcohol
copolymer (C), wherein an isocyanate group content (mole) in raw
materials of the thermoplastic polyurethane (A) is greater than a
hydroxyl group content (mole) therein, an isocyanate group content
(mole) in raw materials of the thermoplastic polyurethane (B) is
nearly equal to a hydroxyl group content (mole) therein, and the
thermoplastic polyurethane (B) and the ethylene-vinyl alcohol
copolymer (C) have a mass ratio (B/C) of from 70/30 to 99/1 and a
content of the thermoplastic polyurethane (A), based on 100 parts
by mass of a total of the thermoplastic polyurethane (B) and the
ethylene-vinyl alcohol copolymer (C), is from 1 to 30 parts by
mass. Thus, a resin composition is provided that contains
thermoplastic polyurethanes and an ethylene-vinyl alcohol copolymer
and is good in melt shapability.
Inventors: |
Isoyama; Kouta; (Okayama,
JP) ; Oshita; Tatsuya; (Okayama, JP) ; Saitou;
Hidekazu; (Ibaraki, JP) ; Ono; Hiroyuki;
(Ibaraki, JP) |
Assignee: |
KURARAY CO., LTD.
Kurashiki-shi
JP
|
Family ID: |
42828177 |
Appl. No.: |
13/259909 |
Filed: |
March 29, 2010 |
PCT Filed: |
March 29, 2010 |
PCT NO: |
PCT/JP2010/055593 |
371 Date: |
September 30, 2011 |
Current U.S.
Class: |
428/423.3 ;
521/40.5; 525/58 |
Current CPC
Class: |
B32B 2307/51 20130101;
B32B 2250/05 20130101; B32B 2250/24 20130101; B32B 27/306 20130101;
B32B 2305/70 20130101; C08L 23/0861 20130101; Y10T 428/31554
20150401; B32B 27/08 20130101; B32B 2272/00 20130101; C08L 75/06
20130101; C08L 2666/02 20130101; B32B 27/40 20130101; C08G 18/0895
20130101; C08L 2205/03 20130101; B32B 2250/40 20130101; C08L 75/06
20130101; B32B 2307/7244 20130101; C08G 18/664 20130101; B32B
2270/00 20130101 |
Class at
Publication: |
428/423.3 ;
525/58; 521/40.5 |
International
Class: |
B32B 27/40 20060101
B32B027/40; B32B 27/28 20060101 B32B027/28; C08L 75/08 20060101
C08L075/08; C08L 75/06 20060101 C08L075/06; C08L 29/02 20060101
C08L029/02; C08J 11/06 20060101 C08J011/06 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2009 |
JP |
2009-081102 |
Claims
1. A resin composition, comprising: (A) a thermoplastic
polyurethane (A), which is a thermoplastic polyurethane obtained by
reacting a polyisocyanate, a high molecular weight polyol, and a
chain extender, and is a thermoplastic polyurethane in which the
high molecular weight polyol comprises polyester polyol or
polyether polyol having a number average molecular weight of from
500 to 8000 and the chain extender comprises a low molecular weight
polyol having a molecular weight of 300 or less, and satisfies
expression (1) 1.02.ltoreq.PIa/(POHa+CLa).ltoreq.1.12 (1) wherein
PIa is content (mole) of isocyanate groups in the polyisocyanate,
wherein POHa is content (mole) of hydroxyl groups in the high
molecular weight polyol, and wherein CLa: content (mole) of
hydroxyl groups in the chain extender; (B) a thermoplastic
polyurethane (B), which is a thermoplastic polyurethane obtained by
reacting a polyisocyanate, a high molecular weight polyol, and a
chain extender, and is a thermoplastic polyurethane in which the
high molecular weight polyol comprises polyester polyol or
polyether polyol having a number average molecular weight of from
500 to 8000 and the chain extender comprises a low molecular weight
polyol having a molecular weight of 300 or less, and satisfies
expression (2) PIb/(POHb+CLb)<1.02 (2), wherein PIb is content
(mole) of isocyanate groups in the polyisocyanate wherein POHb is
content (mole) of hydroxyl groups in the high molecular weight
polyol wherein CLb is content (mole) of hydroxyl groups in the
chain extender; (C) a ethylene-vinyl alcohol copolymer (C), which
is an ethylene-vinyl alcohol copolymer comprising ethylene in a
content of from 20 to 60 mol % and having a degree of
saponification of 90 mol % or more, wherein the thermoplastic
polyurethane (B) and the ethylene-vinyl alcohol copolymer (C) have
a mass ratio (B/C) of from 70/30 to 99/1, and wherein a content of
the thermoplastic polyurethane (A), based on 100 parts by mass of a
total of the thermoplastic polyurethane (B) and the ethylene-vinyl
alcohol copolymer (C), is from 1 to 30 parts by mass.
2. The composition of claim 1, wherein the thermoplastic
polyurethane (B) has a JIS A hardness of from 80 to 95.
3. A method of producing the composition of claim 1, the method
comprising: melt kneading by blending the thermoplastic
polyurethane (A) with a scrap obtained from a multilayered
structure comprising at least one layer of the thermoplastic
polyurethane (B) and at least one layer of the ethylene-vinyl
alcohol copolymer (C).
4. A multilayered structure, comprising: at least one layer of the
composition of claim 1; at least one layer of the thermoplastic
polyurethane (B); and at least one layer of the ethylene-vinyl
alcohol copolymer (C).
5. A method of producing the composition of claim 2, the method
comprising: melt kneading by blending the thermoplastic
polyurethane (A) with a scrap obtained from a multilayered
structure comprising at least one layer of the thermoplastic
polyurethane (B) and at least one layer of the ethylene-vinyl
alcohol copolymer (C).
6. A multilayered structure, comprising: at least one layer of the
composition of claim 2; at least one layer of the thermoplastic
polyurethane (B); and at least one layer of the ethylene-vinyl
alcohol copolymer (C).
7. The composition of claim 1, wherein the polyisocyanate, from
which the thermoplastic polyurethane (A) is obtained, comprises at
least one aromatic diisocyanate.
8. The composition of claim 1, wherein the polyisocyanate, from
which the thermoplastic polyurethane (A) is obtained, comprises at
least one aliphatic diisocyanate.
9. The composition of claim 1, wherein the polyisocyanate, from
which the thermoplastic polyurethane (A) is obtained, comprises at
least one alicyclic diisocyanate.
10. The composition of claim 1, wherein the polyisocyanate, from
which the thermoplastic polyurethane (A) is obtained, comprises at
least one selected from the group consisting of
4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene
diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate,
3,3'-dichloro-4,4'-diphenylmethane diisocyanate, toluylene
diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate,
4,4'-dicyclohexylmethane diisocyanate, and hydrogenated xylylene
diisocyanate.
11. The composition of claim 1, wherein the polyisocyanate, from
which the thermoplastic polyurethane (A) is obtained, comprises
4,4'-diphenylmethane diisocyanate.
12. The composition of claim 1, wherein the high molecular weight
polyol, from which the thermoplastic polyurethane (A) is obtained,
has a number average molecular weight within a range of 700 to
5,000.
13. The composition of claim 1, wherein the chain extender, from
which the thermoplastic polyurethane (A) is obtained, comprises at
least one aliphatic diol having a carbon number of from 2 to
10.
14. The composition of claim 1, wherein the chain extender, from
which the thermoplastic polyurethane (A) is obtained, comprises at
least one selected from the group consisting of ethylene glycol,
propylene glycol, 1,4-butanediol, 1,6-hexanediol,
1,4-bis(.beta.-hydroxyethoxy)benzene, 1,4-cyclohexanediol,
bis(.beta.-hydroxyethyl)terephthalate, and xylylene glycol.
15. The composition of claim 1, wherein the chain extender, from
which the thermoplastic polyurethane (A) is obtained, comprises
1,4-butanediol.
16. The composition of claim 1, wherein the thermoplastic
polyurethane (A) has a ratio [PIa/(POHa+CLa)] of 1.03 or more.
17. The composition of claim 1, wherein the thermoplastic
polyurethane (A) has a ratio [PIa/(POHa+CLa)] of 1.04 or more.
18. The composition of claim 1, wherein the thermoplastic
polyurethane (A) has a ratio [PIa/(POHa+CLa)] of 1.10 or less.
19. The composition of claim 1, wherein the thermoplastic
polyurethane (A) has a ratio [PIa/(POHa+CLa)] of 1.08 or less.
20. The composition of claim 1, wherein the thermoplastic
polyurethane (B) has a JIS A hardness of from 85 to 95.
Description
TECHNICAL FIELD
[0001] The present invention relates to a resin composition
containing thermoplastic polyurethanes and an ethylene-vinyl
alcohol copolymer. It also relates to a method of producing a resin
composition thereof. Further, it relates to a multilayered
structure including a layer of a resin composition thereof.
BACKGROUND ART
[0002] Thermoplastic polyurethanes (hereinafter, may be referred to
as TPU) are used in a wide range of fields due to their excellent
strength, flexibility, an elastic recovery property, abrasion
resistance, and the like. For example, shaped articles, such as a
film, a sheet, a belt, a hose, and a tube, produced by extrusion
molding and shaped articles in a variety of shapes obtained by
injection molding have increasing applications due to their
excellent properties. However, since the gas barrier property of a
TPU is not good in general, a multilayered structure including a
TPU layer and a gas barrier resin layer is used for applications in
which a gas barrier property is required. As this gas barrier resin
layer, there is proposed to use an ethylene-vinyl alcohol copolymer
(hereinafter, may be referred to as EVOH) (for example, Patent
Documents 1 through 3).
[0003] When producing a multilayered structure having an EVOH layer
and a TPU layer, it is inevitable to generate scraps, such as edges
of a multilayered film produced by coextrusion molding, by-product
trimmed chips when producing by coextrusion blow molding, and
further a loss due to poor shaping. Accordingly, it is desired to
try reusing them from the perspective of production cost reduction
and resource saving. However, resin compositions obtained by melt
kneading scraps of a multilayered structure having a TPU layer and
an EVOH layer are often poor in shapability, which hinders reuse of
scraps and there has been a demand for improvement on that
point.
[0004] Reuse of scraps of a multilayered structure having an EVOH
layer has been reviewed variously from before. For example, in
Patent Documents 4 through 6, methods of reusing scraps of a
multilayered structure having an EVOH layer and a hydrophobic resin
layer, such as polyolefin, are described. However, a method of
reusing scraps of a multilayered structure having an EVOH layer and
a TPU layer is not described.
PRIOR ART DOCUMENTS
Patent Documents
[0005] Patent Document 1: JP 58-22163A [0006] Patent Document 2: JP
2-258341A [0007] Patent Document 3: JP 3-5143A [0008] Patent
Document 4: JP 7-195635A [0009] Patent Document 5: JP 11-140244A
[0010] Patent Document 6: JP 2000-248073A
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0011] The present invention is made to solve the above mentioned
problems, and it is an object thereof to provide a resin
composition containing a TPU and an EVOH and having good melt
shapability. It is also an object to provide a preferred method of
producing a resin composition thereof. Further, it is an object to
provide a multilayered structure including a layer of a resin
composition thereof.
Means for Solving the Problems
[0012] The above mentioned problems are solved by providing a resin
composition, comprising: a thermoplastic polyurethane (A); a
thermoplastic polyurethane (B); and an ethylene-vinyl alcohol
copolymer (C), wherein
[0013] the thermoplastic polyurethane (A) is a thermoplastic
polyurethane obtained by reacting a polyisocyanate, a high
molecular weight polyol, and a chain extender and is a
thermoplastic polyurethane in which the high molecular weight
polyol includes polyester polyol or polyether polyol having a
number average molecular weight of from 500 to 8000 and the chain
extender includes a low molecular weight polyol having a molecular
weight of 300 or less, and also which satisfies a following
expression (1)
1.02.ltoreq.PIa/(POHa+CLa).ltoreq.1.12 (1) [0014] PIa: content
(mole) of isocyanate groups in the polyisocyanate, [0015] POHa:
content (mole) of hydroxyl groups in the high molecular weight
polyol, and [0016] CLa: content (mole) of hydroxyl groups in the
chain extender,
[0017] the thermoplastic polyurethane (B) is a thermoplastic
polyurethane obtained by reacting a polyisocyanate, a high
molecular weight polyol, and a chain extender and is a
thermoplastic polyurethane in which the high molecular weight
polyol includes polyester polyol or polyether polyol having a
number average molecular weight of from 500 to 8000 and the chain
extender includes a low molecular weight polyol having a molecular
weight of 300 or less, and also which satisfies a following
expression (2)
PIb/(POHb+CLb)<1.02 (2) [0018] PIb: content (mole) of isocyanate
groups in the polyisocyanate [0019] POHb: content (mole) of
hydroxyl groups in the high molecular weight polyol [0020] CLb:
content (mole) of hydroxyl groups in the chain extender,
[0021] the ethylene-vinyl alcohol copolymer (C) is an
ethylene-vinyl alcohol copolymer having an ethylene content of from
20 to 60 mol % and having a degree of saponification of 90 mol % or
more, and
[0022] the thermoplastic polyurethane (B) and the ethylene-vinyl
alcohol copolymer (C) have a mass ratio (B/C) of from 70/30 to 99/1
and a content of the thermoplastic polyurethane (A), based on 100
parts by mass of a total of the thermoplastic polyurethane (B) and
the ethylene-vinyl alcohol copolymer (C), is from 1 to 30 parts by
mass. At this time, it is preferred that the thermoplastic
polyurethane (B) has a JIS A hardness of from 80 to 95.
[0023] The above mentioned problems are also solved by providing a
method of producing the above mentioned resin composition,
comprising melt kneading by blending the thermoplastic polyurethane
(A) with a scrap obtained from a multilayered structure including
at least one layer of the thermoplastic polyurethane (B) and at
least one layer of the ethylene-vinyl alcohol copolymer (C).
[0024] Further, the above mentioned problems are also solved by
providing a multilayered structure, comprising: at least one layer
of the above mentioned resin composition; at least one layer of the
thermoplastic polyurethane (B); and at least one layer of the
ethylene-vinyl alcohol copolymer (C).
Effects of the Invention
[0025] A resin composition of the present invention is good in melt
shapability. The resin composition can be produced by melt kneading
using a scrap obtained from a multilayered structure having TPU
layers and an EVOH layer, so that it is preferred from the
perspective of producing cost reduction and resource saving. In
addition, a multilayered structure including a layer of a resin
composition of the present invention has a good appearance.
Mode for Carrying Out the Invention
[0026] A resin composition of the present invention contains a TPU
(A), a TPU (B), and an EVOH (C).
[0027] The TPU (A) is a TPU obtained by reacting a polyisocyanate,
a high molecular weight polyol, and a chain extender and is a TPU
in which the high molecular weight polyol includes polyester polyol
or polyether polyol having a number average molecular weight of
from 500 to 8000 and the chain extender includes a low molecular
weight polyol having a molecular weight of 300 or less, and also
which satisfies a following expression (1)
1.02.ltoreq.PIa/(POHa+CLa).ltoreq.1.12 (1) [0028] PIa: content
(mole) of isocyanate groups in the polyisocyanate, [0029] POHa:
content (mole) of hydroxyl groups in the high molecular weight
polyol, and [0030] CLa: content (mole) of hydroxyl groups in the
chain extender.
[0031] The TPU (B) is a TPU obtained by reacting a polyisocyanate,
a high molecular weight polyol, and a chain extender and is a TPU
in which the high molecular weight polyol includes polyester polyol
or polyether polyol having a number average molecular weight of
from 500 to 8000 and the chain extender includes a low molecular
weight polyol having a molecular weight of 300 or less, and also
which satisfies a following expression (2)
PIb/(POHb+CLb)<1.02 (2) [0032] PIb: content (mole) of isocyanate
groups in the polyisocyanate [0033] POHb: content (mole) of
hydroxyl groups in the high molecular weight polyol [0034] CLb:
content (mole) of hydroxyl groups in the chain extender.
[0035] As the polyisocyanates used for synthesizing the TPU (A) and
the TPU (B), various polyisocyanates can be used that are generally
used in producing a TPU. A diisocyanate is usually used as the
polyisocyanates, while it is allowed to use a small amount of a
compound having three or more isocyanate groups, such as a
triisocyanate, in combination as long as not inversely affecting
thermoplasticity. Such a diisocyanate may include, for example,
aromatic diisocyanates, such as 4,4'-diphenylmethane diisocyanate,
tolylene diisocyanate, phenylene diisocyanate, xylylene
diisocyanate, 1,5-naphthylene diisocyanate,
3,3'-dichloro-4,4'-diphenylmethane diisocyanate, and toluylene
diisocyanate; and aliphatic or alicyclic diisocyanates, such as
hexamethylene diisocyanate, isophorone diisocyanate,
4,4'-dicyclohexylmethane diisocyanate, and hydrogenated xylylene
diisocyanate. One type of these polyisocyanates may be used singly,
or two or more types may also be used in combination. Among them,
it is preferred to use 4,4'-diphenylmethane diisocyanate.
[0036] The high molecular weight polyols used for synthesizing the
TPU (A) and the TPU (B) are polyester polyol or polyether polyol
having a number average molecular weight of from 500 to 8000. One
type of these high molecular weight polyols may be used singly, or
two or more types may also be used as a mixture.
[0037] Among the high molecular weight polyols, it is preferred to
use polyester polyol. Polyester polyol can be produced by, for
example, a direct esterification or transesterification reaction of
an ester forming derivative, such as a dicarboxylic acid, an ester
thereof, or an anhydride thereof, and a low molecular weight polyol
in accordance with a conventional method or by ring opening
polymerization of lactone.
[0038] As the dicarboxylic acid constituting the polyester polyol,
those generally used in production of polyester can be used, and
specific examples thereof may include aliphatic dicarboxylic acids
having a carbon number of from 4 to 12, such as succinic acid,
glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic
acid, sebacic acid, dodecanedioic acid, methylsuccinic acid,
2-methylglutaric acid, 3-methylglutaric acid, trimethyl adipic
acid, 2-methyloctanedioic acid, 3,8-dimethyldecanedioic acid, and
3,7-dimethyldecanedioic acid; alicyclic dicarboxylic acids, such as
cyclohexanedicarboxylic acid; and aromatic dicarboxylic acids such
as terephthalic acid, isophthalic acid, orthophthalic acid, and
naphthalenedicarboxylic acid. One type of these dicarboxylic acids
may be used singly, or two or more types may also be used two or
more types as a mixture. Among them, it is preferred to use an
aliphatic dicarboxylic acid having a carbon number of from 6 to 12,
and more preferred to use adipic acid, azelaic acid, or sebacic
acid.
[0039] As the low molecular weight polyol constituting the
polyester polyol, diols generally used in production of polyester
can be used. Specific examples thereof may include aliphatic diols
having a carbon number of from 2 to 15, such as ethylene glycol,
diethylene glycol, triethylene glycol, propylene glycol,
1,3-propanediol, 2-methyl-1,3-propanediol, 1,3-butylene glycol,
1,4-butanediol, 2-methyl-1,4-butanediol, neopentyl glycol,
1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol,
1,8-octanediol, 2-methyl-1,8-octanediol,
2,7-dimethyl-1,8-octanediol, 1,9-nonanediol,
2-methyl-1,9-nonanediol, 2,8-dimethyl-1,9-nonanediol,
1,10-decanediol, and 2,2-diethyl-1,3-propanediol; alicyclic diols,
such as 1,4-cyclohexanediol, cyclohexanedimethanol,
cyclooctanedimethanol, and dimethyl cyclooctanedimethanol; and
aromatic dihydric alcohols, such as
1,4-bis(.beta.-hydroxyethoxy)benzene. One type of these low
molecular weight polyols may be used singly, or two or more types
may also be used as a mixture. Among them, it is preferred to use
an aliphatic diol having a carbon number of from 2 to 6, and it is
more preferred to use 1,4-butanediol or 3-methyl-1,5-pentanediol.
Further, together with the above mentioned diol(s), a small amount
of a trifunctional or higher-functional low molecular weight polyol
can be used in combination. Such a trifunctional or
higher-functional low molecular weight polyol may include, for
example, trimethylolpropane, trimethylolethane, glycerin, and
1,2,6-hexanetriol.
[0040] The lactone used in a case of producing the polyester polyol
by ring opening polymerization of lactone may include
.epsilon.-caprolactone and .beta.-methyl-.delta.-valerolactone.
[0041] The polyether polyol may include, for example, polyethylene
glycol, polypropylene glycol, polytetramethylene glycol, and
poly(methyltetramethylene glycol). One type of these polyether
polyols may be used singly, or two or more types may also be used
as a mixture. Among them, it is preferred to use polytetramethylene
glycol.
[0042] Since the high molecular weight polyols have a number
average molecular weight within a range of from 500 to 8,000, TPUs
are obtained that are more excellent in a mechanical performance
and shapability. The number average molecular weight is preferably
not less than 700 and not more than 5,000. Each of the number
average molecular weights of a high molecular weight polyol in this
context is a number average molecular weight calculated based on a
hydroxyl number measured in accordance with JIS K1577.
[0043] The chain extenders used for synthesizing the TPU (A) and
the TPU (B) are low molecular weight polyols having a molecular
weight of 300 or less and are usually diols. For example, they may
include ethylene glycol, propylene glycol, 1,4-butanediol,
1,6-hexanediol, 1,4-bis(.beta.-hydroxyethoxy)benzene,
1,4-cyclohexanediol, bis(.beta.-hydroxyethyl)terephthalate, and
xylylene glycol. One type of these low molecular weight polyols may
be used singly, or two or more types may also be used as a mixture.
Among them, it is preferred to use an aliphatic diol having a
carbon number of from 2 to 10, and more preferred to use
1,4-butanediol.
[0044] As a method of producing the TPU (A) and the TPU (B), it is
possible to produce using the high molecular weight polyol, the
polyisocyanate, and the chain extender mentioned above and
utilizing a known urethanization reaction technique. At this time,
it is possible to produce either by a prepolymer method or a
one-shot method. Melt polymerization substantially in the absence
of a solvent is preferred, and in particular, continuous melt
polymerization using a multi-shaft screw extruder is preferred.
[0045] In the present invention, it is important that the TPU (A)
satisfies the following expression (1)
1.02.ltoreq.PIa/(POHa+CLa).ltoreq.1.12 (1) [0046] PIa: content
(mole) of isocyanate groups in the polyisocyanate, [0047] POHa:
content (mole) of hydroxyl groups in the high molecular weight
polyol, and [0048] CLa: content (mole) of hydroxyl groups in the
chain extender, and that the TPU (B) satisfies the following
expression (2)
[0048] PIb/(POHb+CLb)<1.02 (2) [0049] PIb: content (mole) of
isocyanate groups in the polyisocyanate [0050] POHb: content (mole)
of hydroxyl groups in the high molecular weight polyol [0051] CLb:
content (mole) of hydroxyl groups in the chain extender.
[0052] Although a ratio [PIa/(POHa+CLa)] in a general TPU used for
melt molding is often less than 1.02 in usual cases, the melt
shapability of a resin composition including such a TPU and an EVOH
has not always been good. For example, in such a case of forming a
film using the resin composition, holes, film surface roughness,
and the like have been prone to be generated and shaped articles
having a good appearance have not been easily obtained. This point
has been a particular problem in such a case of melt molding by
reusing scraps of a multilayered structure having a TPU layer and
an EVOH layer. In this regard, the present inventors have found
that the melt shapability of a resin composition containing an EVOH
becomes good by using a TPU having a ratio [PIa/(POHa+CLa)] of 1.02
or more in combination in addition to a TPU having a ratio
[PIa/(POHa+CLa)] of less than 1.02 and thus have completed the
present invention. Although the mechanism is not altogether clear,
it is considered because a decrease in the molecular weight of the
TPU derived from moisture absorption at the time of melt molding is
effectively suppressed by blending the TPU having a high isocyanate
ratio.
[0053] The TPU (A) satisfies the following expression (1)
1.02.ltoreq.PIa/(POHa+CLa).ltoreq.1.12 (1)
In a case that the ratio [PIa/(POHa+CLa)] is less than 1.02, even
by adding the TPU (A) to a mixture including the TPU (B) and the
EVOH (C), the effect of preventing the decrease in melt viscosity
of the resin composition thus obtained is insufficient. The ratio
[PIa/(POHa+CLa)] is preferably 1.03 or more, and more preferably
1.04 or more. In contrast, in a case that the ratio
[PIa/(POHa+CLa)] exceeds 1.12, it becomes difficult to sufficiently
increase the degree of polymerization of the TPU (A), so that it is
difficult to synthesize a TPU (A) having a preferable logarithmic
viscosity. The ratio [PIa/(POHa+CLa)] is preferably 1.10 or less,
and more preferably 1.08 or less.
[0054] The TPU (B) satisfies the following expression (2)
PIb/(POHb+CLb)<1.02 (2)
There is a possibility of degrading the long term operational
stability in a case that the ratio [PIa/(POHa+CLa)] is 1.02 or
more, in a case that the TPU (B) is obtained by extrusion molding,
or in a case that a resin composition containing the TPU (B) is
obtained by extrusion molding. The ratio [PIa/(POHa+CLa)] is
preferably 1.01 or less. Usually, the ratio [PIa/(POHa+CLa)] is
0.98 or more and is preferably 0.99 or more.
[0055] The TPU (B) preferably has a JIS A hardness within a range
of from 80 to 95. In a case that the JIS A hardness is lower than
80 or is higher than 95, the fatigue resistance, the flexibility,
and the like of the multilayered structure having the TPU layers
and the EVOH layer are degraded. A more preferable lower limit of
the JIS A hardness is 85. Here, the JIS A hardness of a TPU is a
value measured in accordance with JIS K7311. On the other hand, it
is preferred that the TPU (A) also has a JIS A hardness comparable
with that of the TPU (B).
[0056] The TPU (A) preferably has a logarithmic viscosity of 0.85
dl/g or more when measured at 30.degree. C. using a solution
obtained by dissolving the TPU (A) in N,N-dimethylformamide to be
at a concentration of 0.5 g/dl, more preferably 1.0 dl/g or more,
and even more preferably 1.1 dl/g or more. In a case of using a TPU
(A) having a logarithmic viscosity lower than that mentioned above,
there is a possibility of not applying a sufficient shear force
when melt kneading the TPU (A), the TPU (B), and the EVOH (C) and
of making the reaction of the isocyanate groups contained in the
TPU (A) less developing. The TPU (A) usually has a logarithmic
viscosity of 1.5 dl/g or less.
[0057] On the other hand, the TPU (B) preferably has a logarithmic
viscosity of 0.85 dl/g or more when measured at 30.degree. C. using
a solution obtained by dissolving the TPU (B) in
N,N-dimethylformamide to be at a concentration of 0.5 g/dl, more
preferably 1.0 dl/g or more, and even more preferably 1.1 dl/g or
more. By using the TPU (A) having the logarithmic viscosity
mentioned above, shaped articles having less residual strain are
obtained. The TPU (B) usually has a logarithmic viscosity of 1.2
dl/g or less.
[0058] The EVOH (C) used in the present invention is obtained by
saponifying a copolymer of ethylene and a fatty acid vinyl ester,
such as vinyl acetate, using an alkali catalyst or the like.
[0059] The ethylene content of the EVOH (C) is from 20 to 60 mol %.
With the ethylene content of less than 20 mol %, the gas barrier
property at high humidity decreases and the melt shapability is
also degraded. The ethylene content is preferably 25 mol % or more.
In contrast, with an ethylene content of over 60 mol %, a
sufficient gas barrier property is not obtained. The ethylene
content is preferably 50 mol % or less, and more preferably 45 mol
% or less.
[0060] The EVOH (C) has a degree of saponification of 90 mol % or
more, preferably 95 mol % or more, and more preferably 98 mol % or
more. With a degree of saponification of less than 90 mol %, not
only the gas barrier property at high humidity decreases but also
the thermal stability of the EVOH (C) is degraded and gel and hard
spots are prone to be generated in a shaped article thereof.
[0061] The ethylene content and the degree of saponification of the
EVOH (C) can be obtained by a nuclear magnetic resonance (NMR)
method.
[0062] In the EVOH (C), as long as the object of the present
invention is not inhibited, a small amount of another monomer can
also be copolymerized. Examples of the copolymerizable monomer may
include .alpha.-olefins, such as propylene, 1-butene, isobutene,
4-methyl-1-pentene, 1-hexene, and 1-octene; unsaturated carboxylic
acids, such as itaconic acid, methacrylic acid, acrylic acid, and
maleic anhydride, a salt thereof, a partial or complete ester
thereof, a nitrile thereof, an amide thereof, and an anhydride
thereof; unsaturated sulfonic acids or a salt thereof; alkylthiols;
and vinylpyrrolidones. The amount of copolymerization is usually 10
mol % or less and preferably 5 mol % or less.
[0063] The EVOH (C) may also contain from 0.0002 to 0.2 mol % of a
vinylsilane compound as a copolymerization component. In this case,
not only matching of the melt viscosity with the base resin during
coextrusion is improved to enable production of a uniform
coextrusion multilayered film but also the dispersibility in a case
of blending it with another resin is sometimes improved.
Accordingly, it is effective from the perspective of improving the
melt shapability. Here, the vinylsilane compound may include, for
example, vinyltrimethoxysilane, vinyltriethoxysilane,
vinyltri(.beta.-methoxy-ethoxy)silane, and
.gamma.-methacryloxypropylmethoxysilane. Among all,
vinyltrimethoxysilane and vinyltriethoxysilane are used
preferably.
[0064] The EVOH (C) may also contain a boron compound. In that
case, sometimes, the melt viscosity is improved and the
dispersibility when mixed with the TPU (A) and the TPU (B) is
improved, and also it is enabled to shape a uniform coextrusion
multilayered film. The boron compound content is preferably from 20
to 2000 ppm in terms of boron elements, and more preferably from 50
to 1000 ppm. Here, the boron compound may include boric acids,
boric acid esters, borates, and boron hydrides. Specifically, the
boric acids may include orthoboric acid, metaboric acid, and
tetraboric acid, the boric acid esters may include triethyl borate
and trimethyl borate, and the borates may include an alkali metal
salt and an alkaline earth metal salt of the various boric acids
mentioned above and borax. Among these compounds, orthoboric acid
and NaBH.sub.4 are preferred.
[0065] The EVOH (C) may also contain an alkali metal salt of from 5
to 5000 ppm in terms of alkali metal elements. In this case, the
interlayer adhesion and the compatibility are sometimes improved.
The alkali metal salt is more preferably contained from 20 to 1000
ppm in terms of alkali metal elements, and even more preferably
from 30 to 500 ppm. Here, the alkali metal may include lithium,
sodium, and potassium, and the alkali metal salt may include
aliphatic carboxylates, aromatic carboxylates, phosphates, and
metal complexes of monovalent metals. For example, it may include
sodium acetate, potassium acetate, sodium phosphate, lithium
phosphate, sodium stearate, potassium stearate, and a sodium salt
of ethylenediaminetetraacetic acid. Among all, sodium acetate,
potassium acetate, and sodium phosphate are preferred.
[0066] The EVOH (C) may also contain a phosphorus compound of from
2 to 200 ppm in terms of phosphorus elements, more preferably from
3 to 150 ppm, and optimally from 5 to 100 ppm. In a case that the
phosphorus concentration in the EVOH (C) is less than 2 ppm or in a
case that it is more than 200 ppm, there may be a case of causing a
problem in the melt shapability and the thermal stability. In
particular, problems are sometimes prone to be generated that
generates gel-like hard spots and coloration while melt molding
over a long period of time. The type of the phosphorus compound
blended in the EVOH (C) is not limited in particular, and it is
possible to use various acids, such as phosphoric acid and
phosphorous acid, salts thereof, and the like. The phosphate may be
contained in any form of a primary phosphate, a secondary
phosphate, or a tertiary phosphate, and although the cationic
species thereof is also not limited in particular, alkali metal
salts and alkaline earth metal salts are preferred. Among all, it
is preferred to add a phosphorus compound in a form of sodium
dihydrogen phosphate, potassium dihydrogen phosphate, disodium
hydrogen phosphate, or dipotassium hydrogen phosphate.
[0067] A melt flow rate (MFR) (210.degree. C., under a load of 2160
g, based on ASTM D1238) of the EVOH (C) is preferably from 0.1 to
100 g/10 min., and more preferably from 0.5 to 50 g/10 min.
[0068] In the resin composition of the present invention, the TPU
(B) and the EVOH (C) have a mass ratio (B/C) of from 70/30 to 99/1.
In a case that the mass ratio (B/C) is less than 70/30, the TPU (B)
and the EVOH (C) are prone to be crosslinked and the melt
shapability of a resin composition thereof is degraded. The mass
ratio (B/C) is preferably 75/25 or more, and more preferably 80/20
or more. On the other hand, in a case that the mass ratio (B/C)
exceeds 99/1, the problem of degrading the melt shapability is less
likely to be arisen even without blending the TPU (A), and thus
there is a little advantage of employing the resin composition of
the present invention. The mass ratio (B/C) is preferably 98/2 or
less, and more preferably 95/5 or less.
[0069] In the resin composition of the present invention, a content
of the TPU (A), based on 100 parts by mass of a total of the TPU
(B) and the EVOH (C), is from 1 to 30 parts by mass. In a case that
the content of the TPU (A) is less than 1 part by mass, the effect
of preventing a decrease in the melt viscosity of the resin
composition thus obtained is insufficient. The content of the TPU
(A) is preferably 2 parts by mass or more. In contrast, in a case
that the content of the TPU (A) exceeds 30 parts by mass, the melt
viscosity of the resin composition thus obtained becomes too high
and it becomes difficult to be melt molded. The content of the TPU
(A) is preferably 20 parts by mass or less.
[0070] A method of producing a resin composition of the present
invention may be a method of melt kneading the TPU (A), the TPU
(B), and the EVOH (C), and it is not limited in particular. It is
possible to employ a known method of kneading, such as an extruder
and a Brabender. The resin composition obtained by melt kneading
may be shaped directly, and it is also allowed to be produced once
into pellets and then shaped with another shaping machine.
[0071] It is preferred that the resin composition of the present
invention is produced by using scraps of a multilayered structure
as a raw material. That is, a preferable method of producing a
resin composition of the present invention is a method of melt
kneading by blending the TPU (A) with scraps obtained from a
multilayered structure including at least one layer of the TPU (B)
and at least one layer of the EVOH (C). The resin composition of
the present invention has good melt shapability even with those
obtained by using scraps as a raw material, so that reuse of scraps
becomes easy and it is preferred from the perspective of resource
saving. As such a scrap, it is possible to use edges of a
multilayered film produced by coextrusion molding, by-product
trimmed chips when producing by coextrusion blow molding, burrs
when thermoforming, and further waste products due to poor shaping.
The scraps are cut in appropriate dimensions, dried as needed, and
then mixed with the TPU (A).
[0072] The method of shaping a resin composition of the present
invention is not limited in particular, and various methods of melt
molding are employed, such as extrusion molding and injection
molding.
[0073] Shaped articles obtained by shaping the resin composition of
the present invention is not limited in particular, and although it
is allowed to be a shaped article only including the resin
composition, it is preferred to be a multilayered structure having
a layer of the resin composition. A preferred embodiment is a
multilayered structure, including: at least one layer of the resin
composition according to the present invention; at least one layer
of the TPU (B); and at least one layer of the EVOH (C). When B
denotes a layer of the TPU (B), C denotes a layer of the EVOH (C),
and R denotes a layer of the resin composition according to the
present invention, examples of the layer structure are R/B/C/B/R,
R/B/C/B, B/R/C/R/B, B/R/C/B, and the like. A TPU (B) layer and an
EVOH (C) layer can be adhered to each other even without via an
adhesive resin, and a layer of the resin composition according to
the present invention can also be adhered to both of them even
without via an adhesive resin. It is preferred that a layer of the
resin composition according to the present invention is the layer
of the resin composition produced by using a scrap of a
multilayered structure as a raw material.
[0074] A method of shaping a multilayered structure having a layer
of the resin composition of the present invention is not limited in
particular, and although coextrusion molding, coinjection molding,
or the like is employed, coextrusion molding is preferred from the
perspectives of easy production, economy, and the like. The
coextrusion molding may include coextrusion sheet molding,
coextrusion inflation molding, coextrusion blow molding, and
coextrusion lamination. In a case of shaping by coextrusion molding
or coinjection molding, it is desired that the resins forming
respective layers have comparable melt viscosities. In a case that
the resins forming respective layers have largely different melt
viscosities, it causes generation of film surface roughness and
holes. Accordingly, it is important to decrease a difference of the
melt viscosities between the resin composition and the TPU (B) in
the multilayered structure.
[0075] A sheet, a film, parisons, or the like of a multilayered
structure thus obtained can also be reheated to obtain a stretched
shaped article by stretching uniaxially or biaxially. Examples of a
shaping method in that case are thermoforming, roll stretching,
pantograph stretching, inflation stretching, blow molding, and the
like.
[0076] Shaped articles thus obtained are used in various
applications in which a gas barrier property, flexibility, and the
like are required.
EXAMPLES
[0077] The present invention is described more specifically below
by way of Examples.
(1) Synthesis of TPU (A)
[0078] As raw materials, two types of polyester polyol, a
diisocyanate, and a chain extender listed below were used.
[0079] Polyester Polyol (1)
[0080] A polyester diol produced by reacting 1,4-butanediol and
adipic acid, having a hydroxyl number per molecule of 2.00, and
having a number average molecular weight of 1000
[0081] Polyester Polyol (2)
[0082] A polyester polyol produced by reacting
3-methyl-1,5-pentanediol, trimethylolpropane, and adipic acid,
having a hydroxyl number per molecule of 3.00, and having a number
average molecular weight of 1000
[0083] Diisocyanate
[0084] 4,4'-diphenylmethane diisocyanate (hereinafter, may be
abbreviated as MDI)
[0085] Chain Extender
[0086] 1,4-butanediol (hereinafter, may be abbreviated as BD)
[0087] As the polyester polyol, a 98/2 (molar ratio) mixture of the
polyester polyol (1) and the polyester polyol (2) above mentioned
was used. The mixture had a hydroxyl number per molecule of 2.02.
The mixture, the MDI, and the BD were mixed so as to make the
charge ratio to be the values shown as Synthesis Examples 1 through
4 in Table 1, and then continuously melt kneaded using a
multi-shaft screw extruder (25 mm.phi., cylinder temperature of
from 180 to 200.degree. C., die temperature of 200.degree. C.)
Thus, pellets of TPUs (A-1) through (A-4) were obtained. The TPUs
(A-1) through (A-4) thus obtained all had a logarithmic viscosity
of 1.20 dl/g (measured in an N,N-dimethylformamide solvent, at a
concentration of 0.5 g/dl, at 30.degree. C.). Regarding the pellets
thus obtained, the melt flow rates were measured in conditions of
200.degree. C. and a load of 2160 g based on ASTM D1238, and the
respective results were 1.6 g/10 min., 2.0 g/10 min., 2.1 g/10
min., and 1.6 g/10 min. Synthesis Examples for the TPUs (A-1)
through (A-4) are shown in Table 1.
(2) Synthesis of TPU (B)
[0088] A mixture of 61.78 mass % of the polyester polyol (1), 32.21
mass % of the MDI, and 6.02 mass % of the BD was continuously melt
kneaded using a multi-shaft screw extruder (25 mm.phi., cylinder
temperature of from 180 to 200.degree. C., die temperature of
200.degree. C.) to obtain pellets of TPU (B-1). The TPU (B-1) thus
obtained had a logarithmic viscosity of 1.15 dl/g (measured in an
N,N-dimethylformamide solvent, at a concentration of 0.5 g/dl, at
30.degree. C.). Regarding the sample thus obtained, the melt flow
rate was measured in conditions of 200.degree. C. and a load of
2160 g based on ASTM D1238, and the result was 1.6 g/10 min.
Synthesis Example for the TPU (B-1) is shown in Table 1.
TABLE-US-00001 TABLE 1 PIa Molar POHa Molar CLa Molar MDI POH BD
Ratio Ratio Ratio PIa/ TPU Mass % Mass % Mass % *1) *1) *1) (POHa +
CLa) Synthesis A-1 32.35 62.05 5.60 0.5090 0.2465 0.2445 1.037
Example 1 Synthesis A-2 32.45 62.25 5.30 0.5160 0.2499 0.2340 1.067
Example 2 Synthesis A-3 32.56 62.45 4.99 0.5236 0.2536 0.2227 1.100
Example 3 Synthesis A-4 32.21 61.78 6.02 0.4992 0.2418 0.2590 0.997
Example 4 Synthesis B-1 32.21 61.78 6.02 0.5004 0.2400 0.2596 1.002
Example 5 MDI: 4,4'-diphenylmethane diisocyanate POH: High
molecular weight polyol BD: 1,4-butanediol *1) Molar ratio when PIa
+ POHa + CLa = 1
(3) EVOH (C)
[0089] EVOH pellets "EVAL(registered trademark) E105B" (ethylene
content of 44 mol %, degree of saponification of 99.9 mol %, MFR
8.0 g/10 min. at 200.degree. C. under a load of 2160 g) produced by
Kuraray Co., Ltd. were used. Hereinafter, it is referred to as EVOH
(C-1).
Example 1
Melt Kneading Test
[0090] The TPU (B-1) and the EVOH (C-1) were mixed in a state of
pellets at a mass ratio of 95:5 and charged into a Brabender
(manufactured by Toyo Seiki Seisaku-sho, Ltd.) set at 210.degree.
C. to be kneaded for five minutes, and then 10 parts by mass of the
TPU (A-1) was added based on 100 parts by mass of a total of the
TPU (B-1) and the EVOH (C-1). It was melt kneaded for five minutes
and then stopped kneading to take a sample of the resin
composition. Regarding the sample thus obtained, the melt flow rate
was measured in conditions of 200.degree. C. and a load of 2160 g
based on ASTM D1238, and the result was 1.5 g/10 min. The results
are shown altogether in Table 2.
[Film Forming Test]
[0091] The TPU (B-1) and the EVOH (C-1) were mixed in a state of
pellets at amass ratio of 95:5 and charged into a twin screw
extruder (screw diameter of 25 mm, cylinder temperature of
210.degree. C.) manufactured by Toyo Seiki Seisaku-sho, Ltd. and
melt kneaded to obtain pellets of the resin composition. Based on
100 parts by mass of the pellets of the resin composition thus
obtained, 10 parts by mass of pellets of the TPU (A-1) were added
and charged into a single screw extruder manufactured by Toyo Seiki
Seisaku-sho, Ltd. to fabricate a film having a thickness of 100
.mu.m using a coat-hanger die (width of 30 mm, die temperature of
210.degree. C.). During the film forming process for 30 minutes,
holes and the like were not observed in the film and thus the
single layer film formability was good and determined as "A". The
results are shown in Table 2. The single layer film formability was
determined as "A" in a case that defects, such as holes, were not
observed in the film and that a uniform film was obtained during
the film formation for 30 minutes, and as "B" in a case that
defects, such as holes, were generated in the film and film
formation became impossible.
Examples 2 Through 9
Comparative Examples 1 Through 3
[0092] In a same manner as Example 1 other than modifying the mass
ratio of the TPU (B) and the EVOH (C) and the type and the blending
amount of the TPU (A) as shown in Table 2, melt kneading tests and
film forming tests were carried out. The results are shown in Table
2.
TABLE-US-00002 TABLE 2 TPU (A) MFR after Blending Melt TPU (B)/
Amount Kneading Single EVOH (C) Parts by Test Layer Film Mass Ratio
Type Mass *1) (g/10 min) Formability Example 1 95/5 A-1 10 1.5 A
Example 2 95/5 A-2 10 1.2 A Example 3 95/5 A-3 10 0.6 A Example 4
95/5 A-1 20 1.1 A Example 5 95/5 A-2 20 1.0 A Example 6 95/5 A-3 20
0.4 A Example 7 98/2 A-1 10 1.9 A Example 8 90/10 A-1 10 1.1 A
Example 9 80/20 A-1 10 0.9 A Comparative 95/5 -- 0 2.5 B Example 1
Comparative 95/5 A-4 10 2.2 B Example 2 Comparative 95/5 A-1 40
0.01 B Example 3 *1) Blending amount based on 100 parts by mass of
a total of the TPU (B) and the EVOH (C).
Example 10
[0093] The TPU (B-1) and the EVOH (C-1) were mixed in a state of
pellets at amass ratio of 95:5 and charged into a twin screw
extruder (screw diameter of 25 mm, cylinder temperature of
210.degree. C.) manufactured by Toyo Seiki Seisaku-sho, Ltd. and
melt kneaded to obtain pellets of the resin composition. Based on
100 parts by mass of the pellets of the resin composition thus
obtained, 10 parts by mass of the pellets of the TPU (A-1) were
added and mixed in a state of pellets, and they were charged into a
twin screw extruder (screw diameter of 25 mm, cylinder temperature
of 210.degree. C.) manufactured by Toyo Seiki Seisaku-sho, Ltd. and
melt kneaded to obtain pellets of a resin composition (R-1).
[0094] Using the resin composition (R-1) thus obtained, the TPU
(B-1), and the EVOH (C-1), a five-layer sheet (R-1/B-1/C-1/B-1/R-1)
was fabricated in the coextrusion molding conditions below with a
three-type five-layer coextruder. The five-layer sheet thus
obtained had no surface roughness and no irregularity of thickness
was found in each layer. The evaluation results are shown in Table
3. In the multilayered sheet thus obtained, a case of no roughness
on the surface and no irregularity of thickness found in each layer
was defined as A, a case of obtaining a multilayered sheet while
surface roughness and irregularity of thickness were found was
defined as B, and a case of no multilayered sheet obtained due to
surface roughness or holes was defined as C.
[0095] The coextrusion molding conditions were as below.
Layer structure: R-1/B-1/C-1/B-1/R-1
[0096] (Thickness: 400/95/10/95/400: Units in .mu.m)
Extrusion Temperature of Each Resin:
[0097] C1/C2/C3/Die=170/170/220/200.degree. C.
Extruder Specifications of Each Resin:
[0098] TPU (B-1): [0099] 25 mm.phi. extruder, P25-18AC
(manufactured by Osaka Seiki Kosaku K.K.)
[0100] EVOH (C-1): [0101] 20 mm.phi. extruder, a laboratory machine
of ME type CO-EXT (manufactured by Toyo Seiki Seisaku-sho,
Ltd.)
[0102] Resin composition (R-1): [0103] 40 mm.phi. extruder GT-40A
(manufactured by Research Laboratory of Plastics Technology Co.,
Ltd.)
[0104] T die specifications: [0105] For 500 mm width, three-type
five-layer (manufactured by Research Laboratory of Plastics
Technology Co., Ltd.)
[0106] Temperature of cooling roller: 40.degree. C.
[0107] Draw rate: 1 m/min.
Examples 11, 12
Comparative Examples 4 Through 6
[0108] In a same manner as Example 10 other than modifying the TPU
(A) to be blended when melt kneading into the type and the amount
shown in Table 3, five-layer sheets were produced for evaluation.
The results of film formation of the five-layer sheets are shown in
Table 3.
TABLE-US-00003 TABLE 3 TPU (B)/ TPU (A) Multilayered EVOH (C)
Blending Amount Film Mass Ratio Type Parts by Mass *1) Formability
Example 10 95/5 A-1 10 A Example 11 95/5 A-2 10 A Example 12 95/5
A-3 10 A Comparative 95/5 -- 0 C Example 4 Comparative 95/5 A-4 10
B Example 5 Comparative 95/5 A-1 40 C Example 6 *1) Blending amount
based on 100 parts by mass of a total of the TPU (B) and the EVOH
(C)
* * * * *